And being banned in a country that boasts roughly 500,000,000 Internet users is, of course, not exactly an ideal situation for a company aggressively looking for growth worldwide.

Now Facebook is rumored to have recently inked a partnership deal with a Chinese Internet giant in a move to enter the country (which, as some have pointed out, won’t be a walk in the park any way you look at it).

The rumors originate from a message posted on Sina Weibo, a Chinese Twitter-type micro-sharing service, by Hu Yanping, who is director of the Data Center of China Internet and a respected Internet business analyst and former journalist.

“Facebook really is about to enter China, the agreement is signed. A domestic website will work with Facebook to create a new site. This new site is not interlinked with Facebook.com. Will this live or die in China?”

At the end of last year, Facebook founder and CEO Mark Zuckerberg traveled to China, quite visibly. Though labeled as a personal vacation, he met with a bunch of interesting business people there, including Robin Li, the billionaire co-founder of Baidu, China Mobile CEO Wang Jianzhou, Sina.com CEO Charles Chao and the head of Alibaba Group, Jack Ma.

The Wall Street Journal noted at the time:

The trip appeared to be an effort by the 26-year-old to learn more about the Chinese market, rather than discuss any specific business proposals. But it came as the Facebook founder openly has discussed a desire to get into China, where the government has blocked access to the site since last year.

At an earlier talk to aspiring entrepreneurs at Y Combinator’s Startup School, Zuckerberg indeed expressed hopes to figure out the “right partnerships that we would need to do in China to succeed on our terms.”

“Before we do anything there, I’m personally spending a lot of time studying it and figuring out what I think the right thing to do is,” he said, according to the WSJ. “It’s such an important part of the world. How can you connect the world if you leave out 1.6 billion?”.

So which partnership, exactly, has been signed, at least according to YanPing?

If the rumors are true, Facebook likely reached an agreement with Sina, the largest Chinese-language infotainment web portal, or Baidu, the Chinese search engine juggernaut, or perhaps even both.

If it enters China, partnerships with a local Internet giant happens to be the right way to move forward. It’s worth noting Facebook will have to compete against the likes of Tencent’s PengYou and QZone, 51.com and RenRen and Kaixin001.

Coincidentally, the latter is rumored to shoot for an IPO in the U.S., the WSJ reported this morning.

We’ve contacted Facebook for comment and will update when we hear back.